The high degree of integration of semiconductor devices is accompanied with very fine interconnections and isolation widths required in manufacturing processes. Fine patterns are typically created by forming a resist pattern according to a photo-lithographic technique and etching various types of underlying thin films via the resist pattern used as a mask.
In this sense, the photo-lithographic technique is very important as a starting point for the fine processing. The photo-lithographic technique includes resist coating, mask alignment, exposure to light and development. This technique limits the fineness due to the restriction imposed on the wavelength of exposing light.
As described above, when using the conventional photo-lithographic technique, it has been difficult to form a fine resist pattern which exceeds the limit of the wavelength.